Long Beach , California -LRB- CNN -RRB- -- It was after the robotic hummingbird flew around the auditorium -- and after a speaker talked about the hypersonic plane that could fly from New York to the West Coast in 11 minutes -- that things got really edgy .

Vijay Kumar , an engineering professor at the University of Pennsylvania , showed the more than 1,300 attendees at last week 's TED conference several videos in which fleets of tiny flying robots performed a series of intricate manuevers , working together on tasks without colliding or interfering with each others ' flightworthiness .

It seemed that , at least for some in the audience , a bridge had been crossed into a new era of technology , one that could change the way we think about robots and their application to such fields as construction , shipping and responding to emergencies .

Kumar 's devices -LRB- he calls them `` Autonomous Agile Aerial Robots '' -RRB- cooperated on building simple structures and showed they were capable of entering a building for the first time and quickly constructing a map that would allow for assessment and response to a structural collapse or fire .

He held up one robot , designed by his students Daniel Mellinger and Alex Kushleyev , which weighs a little more than a tenth of a pound and is about 8 inches in diameter . The device has four rotors ; when they spin at the same speed , the robot hovers . If you increase the speed , Kumar explained , the robot flies up . Spinning one rotor faster than the one opposite it causes the robot to tilt . It also can flip over multiple times without losing its ability to fly and can recover its stability when thrown into the air .

The robots are capable of learning trajectories and manueuvers that can enable them to literally fly through hoops -- and other confined spaces .

When the robots are formed into a flotilla , they calculate -LRB- a hundred times a second -RRB- and maintain a safe distance between them . He showed a video of 20 robots flying in a variety of formations -- and moving through obstacles -- inches from each other without interfering with the stability of their neighbors .

To cap his presentation , he showed a video , created by his students in three days , of nine flying robots playing the James Bond theme on musical instruments .

TED began in the 1980s with the intention of focusing on `` Technology , entertainment and design , '' and its conferences typically are sold out , attracting an audience of high achievers willing to pay $ 7,500 to attend . TED , a nonprofit , makes many of the talks freely available on its site . -LRB- CNN has a partnership with TED in which it regularly publishes selected TED Talks -RRB- .

TED aims to feature cutting-edge technology at its conferences , and this year 's event , labeled `` Full Spectrum , '' was no exception . Yet the uneasy balance between technology and the social issues it spawns seemed to be highlighted more than ever as speakers took the stage to give their talks -LRB- and be filmed by eight high-def cameras for eventual viewing on the web -RRB- .

In the first session Tuesday , a sharp contrast was drawn between the unbounding optimism that a technological solution could be found for every one of the Earth 's problems and a vision of a planet headed for doom due to mankind 's inability to control its inventions and its consumption .

Paul Gilding , former head of Greenpeace , declared `` the Earth is full , full of us , full of our stuff , full of our waste and full of our demands , '' and warned of harsh and potentially violent disruption ahead as the reckoning comes for a planet living beyond its means . The idea that the planet can sustain 9 billion people without making disruptive changes is wrong , he said .

Peter Diamandis , founder of the X Prize , countered with a catalogue of the ways technology has radically improved our lives -- it has lengthened the human lifespan , conquered many killer diseases , expanded economic opportunity and made possible a worldwide web of communication , already connecting 2 billion people , with 3 billion more on the way to logging in this decade .

`` Technology is a resource-liberating force , '' he said , maintaining that a planet bathed in solar energy and covered with water wo n't lack the ingredients for a productive life .

For every tech evangelist , though , there was a cautionary note sounded by other speakers .

NASA scientist James Hansen , one of the leading voices warning of global climate change due to carbon emissions , presented an urgent case for taking action to deal with the effects of economic activity before ice caps melt and cities get inundated by dramatic rises in sea level .

But an MIT professor , Donald Sadoway , offered reason to hope that the use of non-carbon-emitting solar and wind power could become much more widespread through a new battery technology he and his students are developing to store power for use at times when the wind stops and the sun sets . Sadoway , whose work has attracted an investment from Bill Gates , said successful use of his `` liquid metal battery '' could reduce the need for new fossil-fuel burning power plants .

Regina Dugan , who demonstrated the robotic hummingbird and directs the Defense Advanced Research Projects Agency , talked of research on a prosthetic arm controlled by thoughts alone , of sturdy cars built with metals lighter than Styrofoam and of a robot that can run like a cheetah .

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And yet technology did n't seem to have a solution for the problems highlighted by Bryan Stevenson , director of the Equal Justice Initiative . He talked of the rise in the number of imprisoned Americans from 300,000 40 years ago to 2.3 million today , the large number of black Americans who have been permanently deprived of their ability to vote due to prosecution on low-level drug offenses and the question he said is posed by the death penalty -- not whether criminals deserve to die , but whether America as a society , deserves to kill .

Stevenson 's talk drew a standing ovation -- and the following day , after TED curator Chris Anderson appealed for funds , Anderson said $ 1.12 million had been raised for Stevenson 's nonprofit on the spot .

A longtime enthusiast for digital technology , MIT professor Sherry Turkle , spoke of being on the cover of Wired magazine when her book `` Life on the Screen '' was published in the 1990s . In her new and darker book , `` Alone Together , '' she writes of everyday family and social relationships put at risk by the compulsion to interact constantly with mobile devices as a substitute for face-to-face interaction .

People text during board meetings , shop and text during class , and even text during funerals , she said . Technology gives us the illusion of being constantly in touch with people , yet we shirk the real demands of friendship . And Turkle pointed out that Japanese researchers are developing robots to provide care to the elderly and to children .

As if to emphasize her point , a day after her talk , Danish scientist Henrik Scharfe demo'ed Geminoid-DK , a shockingly realistic robot version of himself . While its movement and speech is limited , the robot 's technology is likely to evolve quickly .

And so it seemed that it was n't only in jest that Scharfe said , `` Ten years from now , I 'll be at home having a beer in Denmark and the robot will come to TED to give a talk . ''

Scharfe said after his talk that he recognized the dangers Turkle talked about , but he thought developing the robot was well worth doing .

`` This can never be about replacing the human being , '' he said in his talk , `` but about using technology to understand the full spectrum of being human . ''

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Vijay Kumar demonstrated fleets of flying robots that could revolutionize industries

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Kumar spoke at the TED2012 conference , `` Full Spectrum , '' in California

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Talks highlighted the contrast between technological progress and social issues

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Technology has improved health , lifespan , productivity , yet it poses challenges , speakers said